Primers for short fragments of single stranded DNA (oligonucleotides) play a very important role in biotechnology, such as PCR amplification, DNA sequencing and other experiments. Our technical service center adopts international advanced DNA synthesizer, which can accurately synthesize various types of primers for customers.

Primer purification:

C18 column desalination

Also known as simple reversed-phase column, it has specific adsorption on DNA and can be eluted by organic solution, but will not be washed off by water. Therefore, it can effectively remove salt, but can not effectively remove small fragments shorter than the target fragment. This method generally does not affect the ordinary PCR reaction. This level cannot be used for citations that need to be used for sequencing and cloning. 
RPC purification
RPC purification is the purification of primers through reverse phase cartridge. The purification principle is the same as that of reverse phase HPLC. Compared with RP-HPLC, RPC is an effective and more economical purification method. The reverse phase purification filter element usually contains a hydrophobic matrix, such as C18 silica gel, which can adsorb DNA well, and can easily wash the cut protective group and short lead fragment from the reverse phase column with water. RPC purified primers can be used in DNA sequencing, PCR and gene synthesis.
Page purification
PAGE purification method is using denaturing polyacrylamide gel electrophoresis to separate the Toxoplasma DNA, and then recover the target DNA from the gel. Page purification method is also a very effective DNA purification method. The purified DNA purity is more than 90%, which is particularly effective for the purification of long-chain oligo DNA (more than 50 MER).
HPLC purification
HPLC purification uses the principle of high performance liquid chromatography to purify bow DNA. The method can achieve high purity and sensitivity when used for separation, purification or analysis. Ion exchange HPLC and reverse phase HPLC are commonly used in the analysis and purification of primer DNA. Reverse phase HPLC: the purity is more than 90%; Ion exchange HPLC: the purity is more than 95%, which can effectively remove the short fragment of n-1. HPLC purification is mainly used for the purification of short chain and modified bow. The disadvantages of this method are high cost and low mass production efficiency.
Modified primer:
Group modification:Thio modification, rare base (DI, Du), modification group (amino, biotin, digoxin, sulfhydryl, phosphorylation).
Fluorescent marking:FAM、TAMRA、FITC、TET、HEX、Cy3、Cy5 And so on.。
Double labeled fluorescent probe:The 5 'end of the probe is labeled with fluorescent group and the 3' end is labeled with quenching group. The combined purification method is adopted to ensure the quality of the probe.
Molecular beacon:The stem ring double labeled oligonucleotide probe with hairpin structure has complementary nucleic acid sequences at both ends, with - end labeled fluorescent group and the other - end labeled quenching group. In the free state, the two groups are close to each other and fluorescence quenching; Combined with the target sequence, the molecular beacon configuration changes and the fluorescence is restored.
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